Chapter 48: Somatic Sensations PDF

Chapter 48: Somatic Sensations: I. General Organization, the Tactile and Position Senses Hall: Guyton and Hall Textbook of Medical Physiology, 14th Edition MULTIPLE CHOICE 1. For a sensory nerve fiber that is connected to a Pacinian corpuscle located on the palmer surface of the right hand,...

Chapter 48: Somatic Sensations: I. General Organization, the Tactile and Position Senses Hall: Guyton and Hall Textbook of Medical Physiology, 14th Edition MULTIPLE CHOICE 1. For a sensory nerve fiber that is connected to a Pacinian corpuscle located on the palmer surface of the right hand, the synaptic connection with the next neuron in the appropriate sensory pathway is in which of the following? a. Right dorsal column nucleus b. Left dorsal column nucleus c. Dorsal horn of right side of spinal cord d. Dorsal horn of left side of spinal cord ANS: A 2. For a sensory nerve fiber that is connected to a free nerve ending located on the left hand, the synaptic connection with the next neuron in the appropriate sensory pathway is in which of the following? a. Right dorsal column nucleus b. Left dorsal column nucleus c. Dorsal horn of right side of spinal cord d. Dorsal horn of left side of spinal cord ANS: D 3. The second neuron in the appropriate sensory pathway that connects a Meissner corpuscle in the left palm to the somatosensory cortex travels in the a. contralateral lateral lemniscus. b. ipsilateral anterolateral column. c. ipsilateral medial lemniscus. d. contralateral medial lemniscus. ANS: D 4. The second neuron in the appropriate sensory pathway that connects a free nerve ending in the left thumb to the somatosensory cortex travels in the a. ipsilateral anterolateral column. b. ipsilateral medial lemniscus. c. contralateral anterolateral column. d. contralateral medial lemniscus. ANS: C 5. A 36-year-old male involved in a motor vehicle collision received an injury to the spine at C7 that transected the right half of the spinal cord. During the physical examination of this patient, two-point discrimination (fine touch) would a. be absent on left side of body. b. be absent on right side of body. c. not be affected by injury.  d. be enhanced on right side. ANS: B 6. A 32-year-old female involved in a motor vehicle collision received an injury to the spine at C5 that transected the left half of the spinal cord. On which side of the patient would you expect pain and temperature sensations to be absent? a. Left side b. Right side c. Neither side d. Both sides ANS: B 7. A 31-year-old male involved in a motor vehicle collision received an injury to the spine at C7 that transected the left half of the spinal cord. On which side of this patient would you expect vibration sense to be absent? a. Left side b. Right side c. Vibration sensation would be not be affected d. Both sides ANS: A 8. A 31-year-old male involved in a motor vehicle collision received an injury to the spine at C7 that transected the left half of the spinal cord. On which side of this patient would the position sensation (proprioception) be absent? a. Left side b. Right side c. Proprioceptive sensation would not be affected d. Both sides ANS: A 9. An individual was brought into the emergency department following a motor vehicle collision. The individual is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination of this individual, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg including the hand and foot, loss of pain and temperature sense in the right arm and leg including the hand and foot. The loss of fine touch and vibration sense involves which of the following nerve tracts in this patient? a. Anterolateral system b. Dorsal column system c. Corticospinal tract d. Medial forebrain bundle ANS: B 10. An individual was brought into the emergency department following a motor vehicle collision. The individual is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination of this individual, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg including the hand and foot, loss of pain and temperature sense in the right arm and leg including the hand and foot. The loss of pain and temperature sense involves which of the following nerve tracts in this patient? a. Corticospinal tract b. Pontocerebellar tract c. Dorsal column system d. Anterolateral system ANS: D 11. An individual was brought into the emergency department following a motor vehicle collision. The individual is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination of this individual, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg including the hand and foot, loss of pain and temperature sense in the right arm and leg including the hand and foot. One can rule out a lesion in which of the following areas of the nervous system? a. Cortex b. Brain stem c. Peripheral nerves d. Spinal cord ANS: A 12. An individual was brought into the emergency department following a motor vehicle collision. The individual is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination of this individual, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg including the hand and foot, loss of pain and temperature sense in the right arm and leg including the hand and foot. Which of the following is the most likely location of the injury to the nervous system in this patient? a. Left side of cervical spinal cord b. Right side of cervical spinal cord c. Brain stem involving left medial lemniscus d. Left side of lumbar spinal cord ANS: A 13. An individual was brought into the emergency department following a motor vehicle collision. The individual is conscious and reports no loss of consciousness during the incident. There is no physical evidence of any head trauma. However, upon examination of this individual, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg including the hand and foot, loss of pain and temperature sense in the right arm and leg including the hand and foot. Which of the following areas of the body has the greatest area of representation in the primary somatosensory cortex? a. Foot b. Face c. Trunk d. Forearm ANS: B 14. Which of the following nerve structures carries axons from the dorsal column nuclei to the thalamus? a. Spinothalamic tract b. Lateral lemniscus c. Mammillothalamic tract d. Medial lemniscus ANS: D 15. A progressive rise in receptor potential (becomes less negative) of a typical mechanoreceptor is most likely to have which of the following effects on the frequency of action potentials in the axon from that mechanoreceptor? a. Proportional decrease b. Proportional increase c. No change d. Ten-fold decrease e. Ten-fold increase ANS: B 16. Which of the following sensory receptors is most likely to have the highest rate of adaptation? a. Free nerve endings b. Meissner corpuscle c. Merkel cell-neurite complex d. Pacinian corpuscle e. Ruffini ending ANS: D 17. The third afferent neuron from a typical mechanoreceptor is most likely to terminate in which of the following structures? a. Amygdala b. Locus coeruleus c. Periaqueductal gray d. Primary motor cortex (layer IV)  e. Primary motor cortex (layer V) f. Primary somatosensory cortex (layer IV) g. Primary somatosensory cortex (layer V) h. Ralph nucleus ANS: F 18. Which of the following best describes the number of neurons in series from a typical sensory receptor to the somatosensory cortex? a. 1 b. 2 c. 3 d. 4 e. 5 ANS: C 19. Which of the following structures has the greatest area of representation in the somatosensory cortex? a. Genitalia b. Lips c. Back d. Toes e. Legs ANS: B 20. Which of the following serves to improve the two-point discrimination threshold in the fingers of a typical human being? a. Lateral inhibition b. Action potential c. Spatial resolution d. Pain e. Damage ANS: A 21. All the following somatic sensations are transmitted in the anterolateral system except one. Which one is the exception? a. Pain sensations b. Thermal sensations c. Sexual sensations d. Vibration sensations e. Tickle and itch sensations ANS: D 22. All the following somatic sensations are transmitted in the dorsal column-medial lemniscal system except one. Which one is the exception? a. Position sensations from joints b. Vibratory sensations c. Touch sensations that require a high degree of localization d. Tickle and itch sensations e. Sensations of movements against the skin ANS: D